Safety cranking device



- o. CROCKETT SAFETY CRANKING DEVICE Filed July 26 1921 Patented May 22, 1323..

UNHTED STATES ins-east Parent cranes,

OSCAR CROCKET'I, OF KANSAS CITY, MISSOURI, ASSIGNOR OF ONE-HALF TO WALTER B.

GROCKETT, OF KANSAS CITY, MISSOURI.

SAFETY CRANKING DEVICE.

Application filed July 26, 1921.

To all whom it may concern:

Be it known that I, Osonn Cnoonn'r'r, a citizen of the United States, residing at Kansas City, in the county of Jackson and State of Missouri, have invented certain new and useful Improvements in Safety Cranking Devices, of which the following is a specification.

The present invention relates to a safety construction for manually operated engine cranking devices such as are commonly employed for starting internal combustion engines, and has for its object to provide a construction of this character which embodies novel features whereby it will act very quickly as well as in a positive and reliable manner to disengage the hand crank from the engine shaft and thereby prevent injury to the operator in the event the engine back-fires.

I am aware of the fact that there are prior patents upon engine cranking devices which have this general object in view, although the constructions of these prior devices are not entirely satisfactory and are open to quite a number of practical objections. In a device of this character the clutch mechanism must be one that is absolutely reliable in its operation and which will act immedi- 30 ately without any reverse movement in order that the hand crank may be disengaged from the engine shaft before it has made more than a small fraction of a backward revolution when the engine back-fires. There is always a certain amount of back play in a pawl and ratchet construction. and the shock incident to use in a device of this character is such that breakage of some of the parts in a pawl and ratchet construction would be liable to take place. Furthermore, the device must be simple in its construction and adapted to be applied without any material changes or alterations to those types of engines which are already in extensive use. p

The object of the present invention has been to provide a safety cranking device which is free from the objectionable features found in prior devices having the same object in view, and which can be applied without difficulty to the conventional cranking devices of engines and automobiles.

With these and other objects in view, the invention consists in certain combinations and arrangements of the parts as will be Serial No. 487,788.

shown more fully as the description proceeds, the novel features thereof being pointed out in the appended claims.

For a full understanding of the invention, reference is to be had to the following description and accompanying drawings, in which:

Figure l is a front elevation of a safety cranking device constructed in accordance with the invention, portions being broken away and a fragmentary portion of an automobile frame to which the device is applied being indicated by dotted lines.

Figure 2 is a side elevation of the safety cranking device, portions of the crank being broken away.

Figure 3 is a vertical sectional view through the bearing plate and associated clutch mechanism, the section being taken on the line 3-3 of Figure 1, and

Figure 4C is a top plan view of the bearing member.

Corresponding and like parts are referred to in the following description and inclicated in all of the views of the drawings by like reference characters.

Referring to the drawings, which illustrate a preferred embodiment of the inven tion, the numeral 1 designates a hand crank which is provided at the inner end of the shaft portion thereof with a conventional clutch member 2 for engagement with the engine shaft (not shown). The shaft portion of the hand crank 1 extends through a bearing plate 3 which is suitably secured to the frame of the engine and the crank is mounted to have both a sliding movement and a rotary movement. The sliding movement enables it to be moved into and out of clutch engagement with the engine shaft in the usual manner, while the rotary movement is necessary for turning the engine shaft when cranking or starting the engine. This is the usual manner of constructing and mounting these hand cranks and this part of the construction will undoubtedly be clearly understood without further de scription.

The bearing plate or member 3 which is used in carrying out the present invention has a special formation. having one face thereof recessed to provide a chamber within which a clutch disc 4 is mounted. A retaining plate 5 which is detachably secured to the bearing member 3 by suitable fastening members such as; the screws 6 is utilized to keep-the clutch disc, in operative position within'the recess, and this retaining plate is provided with a central opening through which a hubmember 7' which is integral with the clutch disc projects. The bearing plate 3 fits against the front of a portion of the frame of the automobile, such as that indicated at 8 by dotted lines, and. is provided with integral ears 9 which project laterally from op posite sides thereof and are also deflected re'arwardly, said ears having openings therein for engagement with fastening. members such as. the bolts 10 by means of. which the bearing member is rigidly secured. in position. The bearing. member is preferably constructed so that it.

can be substituted for the usual bearing found upon automobiles, although the arrangement is. suchthat thebearing plate is larger than the conventional bearing. This enables a, comparatively large clutch disc 4 to be utilized, and, owing to the. fact that the. clutch members act at a distance from w the shaft they have a more. powerful and effective clutching action and arev more dependable. than they. would be if arranged closeto the shaft.

The peripher y of the clutch disc 4 isipro- 'vided with a plurality of cam notches 11 which receive clutch balls 12. Springs 13 are interposed between these clutch balls and; the shoulders. at the. large'ends of the cam; notches, and; the clutch balls are thus always held in proper position to be instantly brought into action upon any tendency totunn the) clutch disc in a backward direction. The; arrangement Off the cam notches; and clutch balls is such that the ;clutch pl ate is, free. to turn in the same direction as the engine shaft, although it is positively locked against turning in the re- Verse direction, The conventional construction; of; engine is such that they are intended; to. operate in a clock-wise direction, and the a rangemei it of the cami'notches shown on the drawings is such that the clutch disc. 4 is free; to. turn, in a clockwise direction although it is locked. against rotation in a counter-clockwise direction.

15, extends lateraliy through the shaft portion of the hand crank and the projecting ends of this pin are provided with antifriction rollers 16. A spring (not shown) which may be ofany conventional type, may be associated with the hand crank for moving the shaft portion thereof longitudinally to hold the clutch member 2 thereof normally disengaged from the engine shaft.

In order to crank the engine the hand crank is moved inwardly and brought into a clutch engagement with the engine shaft, This movement of the hand crank simultaneously brings the projecting ends of the pin 15 into the cam notches. 14 of the hub 7. Upon rotation of the hand crank in a clock wise direction to start the engine, the ends of the pin 15 engage the square ends of the notches 14 and cause the hub 7 and clutch disc 4 to rotate with the hand crank. If the engine starts'in the proper mannerthe hand crank 1 is disengaged from the engine shaft by thct'eeth of the clutch 2 in the usualmanner. However, if the engine back-fires and. the engine shaft starts to rotate in a counterclockwise direction the clutch balls 12 instantly come into action to prevent any corresponding rotation of the clutch disc 4 and hub member 7 The hand crank 1 then moves independently of the clutch disc 4, with the result that the anti-friction rollers 16 ride upon the inclined sides ofthe cam. notches 14, and move the hand crank longitudinally to disengage it from the engine shaft. The inclined ends of the cam notches 1 are arranged at a sharp angle so that the hand crank is disengaged from the. engine shaft before it has made more than a very small fraction of a backward 'turn, and all possibility of injury to the operator is thereby avoided. This action isnot only quick but is also positive for the reason that the clutch balls 12; are always held, in position for ac tion by the springs 13 and the clutch disc 4:; is sufiicientlylarge to admit of the clutch balls being arranged at a comparatively great distance from the axis of the shaft. Furthermore, the safety device has av simple and sturdy construction which will; withstand hard usage and which can be readily substituted for the conventional. hand; crankingdevice.

Having. thus described my invention'what I claim as new and desire to secure by Letters. Patent is:

1. In a safety cranking device for englnes, the combination with a startingcrank provided with a clutch member adapted to en; gage the engine shaft, a bearing member on which said starting crank is slidably and rotatably mounted, said bearing member be-' ing formed with a depression or recess, a clutch disk within said recess or depresslon. and clutch means interposed between the clutch disk and the bearingmember, said clutch means permitting movement of the clutch member in one direction only, said clutch disk having a hub portion with notches therein having cam portions, projections on said starting crank to engage said notches upon movement in one direction and to be forced from said notches by said cam portions upon movement in the other direction, and a cover plate for said bearing 1nemher, said cover plate being apertured to re ceive the hub portion of the clutch disk and provide a bearing therefor and to retain said clutch disk in proper position within said bearing.

2. In a safety cranking device for engines, the combination with a starting crank adapted to engage the crank shaft of an engine upon longitudinal movement thereof in one direction and disengage said crank shaft upon movement in the other direction, a bearing member for said starting crank fixed to the frame of the engine, said bearing member being formed with a disk terminating in a flanged rim having an internal concave faced rim forming a circular race, a clutch disk having peripheral cam faces circumferentially concaved, and clutch means retained between said concave rim and said concave cam faces adapted to positively clutch the same upon movement in one direction and unclutch it upon movement in the other direction, said clutch disk being loosely journaled on said starting crank and having a reduced hub portion extending laterally therefrom, said hub portion being formed with notches having cam surfaces adjacent thereto, lateral projections on said starting crank adapted to engage said notches upon movement in one direction and be forced therefrom by said cam portions upon movement in another direction, an apertured retaining plate for said clutch disk, said retaining plate providing a journal for said hub portion, and means to secure said plate to said bearing member.

3. In a safety cranking device for engines, the combination with a hand crank mounted to rotate and move longitudinally and having a clutch member adapted to engage the engine shaft, a comparatively large recessed and fixedly mounted bearing member, a clutch disc loosely received within the recessed portion of the bearing member and formed with a hub member through which the hand crank extends and which has cam notches in the end thereof, a retaining plate fitted to the bearing member to hold the clutch disc in position and formed with an opening through which the hub member projects, clutch members cooperating with the clutch disc to permit rotation thereof in one direction and prevent rotation thereof in the opposite direction, the clutch disc being comparatively large and the clutch members acting at the periphery thereof so that an effective clutch action is obtained, and arms projecting laterally from the hand crank and arranged to enter the cam notches of the hub when the hand crank is moved longitudinally to bring it into engagement with the engine shaft, said arms cooperating with the notches to rotate the hub and clutch disc with the hand crank when the latter is turned in one direction and to move the hand crank longitudinally to disengage it from the engine shaft when the hand crank is rotated in the opposite direction.

In testimony whereof I afiix my signature.

OSCAR CR-OCKETT. 

